Key member to prevent accidental release of a fluorescent tube from its socket



Dec. 1, 1953 L. J. SKLENAR 2,661,462 KEY MEMBER TO PREVENT' ACCIDENTAL RELEASE OF A FLUORESCENT TUBE FROM ITS SOCKET Filed March 6, 1951 Patented Dec. 1, 1953 KEY MEMBER TO PREVENT ACCIDENTAL RELEASE OF A FLUORESCENT TUBE FROM ITS SOCKET Lester J. Sklenar, Chicago, Ill., assignor to Illinois Tool Works, Chicago, 111., a corporation of Illinois Application March 6, 1951, Serial No. 214,180

4 Claims. 1

This invention relates generally to quickly operable fastening devices, and more particularly to a quickly operable fastener stud made of electrically non-conductive material and adapted to be mounted on fluorescent tube socket fixtures to prevent unauthorized or inadvertent removal of a mounted fluorescent tube therefrom.

The present invention is concerned with solving a problem which is primarily one of safety in the use of fluorescent tubes. It is not uncommon, because of vibration or other factors which are often present, to cause the release and precipitation of fluorescent tubes from their sockets, with the resultant possibility of damage to persons or property in the vicinity. This potential hazard is positively eliminated by the use of the safety key device, to which this invention is primarily directed, and this device is more fully described in later paragraphs. It is therefore an object of the present invention to provide a key or stud made of electrically non-conductive material which can be used in a majority of present types of installations to prevent unauthorized or inadvertent release of a fluorescent tube from its socket.

It is a further object of the present invention to provide a key or stud of the type described which includes means for retaining the stud in mounted position on the socket, said retaining means being releasable by an operator to enable withdrawal of the fastener and thereby permit removal of fluorescent tubes for replacement, inspection, etc.

It is still a further object of this invention to provide a one-piece stud fastener of the type described which may be very economically produced and which is designed so as to not detract from the appearance of present installations when used therewith, and further to enable the use thereof with many various sizes and designs of present commercial sockets.

It is still another object of the invention to provide a safety key or stud of the type heretofore mentioned having means thereon which indicates at a glance the relative position of the fastener to the socket, thereby assuring an inspector that the installation is secured and that the hazard of a falling light tube is not present.

The foregoing and other objects and advantages will be more apparent from the following detailed description when considered in connectionwith the accompanying drawings, wherein:

Fig. 1 is a perspective view of a fluorescent tube installation including the socket portion in which the tube is mounted, and shows the safety key mounted-thereon;

Fig. 2 is a perspective view of one embodiment of the safety key contemplated by the present invention;

Fig. 3 is a plan View of one form of socket with the safety key ready for insertion therein;

Fig. 4 is a view of a fluorescent tube socket similar to Fig. 3 after insertion and rotation of the safety key to mounted position relative thereto;

Fig. 5 shows still another embodiment of safety key contemplated by the present invention;

Fig. 6 shows a plan view similar to Fig. 4 with the safety key of Fig. 5 mounted thereon and positioned to prevent inadvertent or unauthorized removal of the fluorescent tube from the socket member; and

Fig. 7 is a transverse sectional View taken along the line 1-1 of Fig. 4.

Referring now to the drawing more in detail, wherein like numerals have been employed to designate various parts throughout the several views, it will be seen that one embodiment of the present invention constitutes a safety key or fastener designated by the numeral 29. The safety key 2:! is comprised of a shank portion 22 having a head 24 at one end thereof and a holding lug 26 axially spaced therefrom and extending radially outwardly from said shank. It is contemplated that the safety key 2il, as shown in Fig. 2, will be fabricated of electrically non-conductive material, such for example as nylon, polystyrene or the like. This is necessary in view of the fact that the present safety key or fastener is so fabricated that when it is in mounted position the lug 26 is located in the vicinity of the electrical contacts within the fluorescent tube socket.

It will be seen by a study of the safety key device shown in Fig. 2 as well as other embodiments disclosed that the invention contemplates means in the form of a nub or protuberance 30 to pre' vent rotation of the fastener after it has been mounted on the socket member 28. The nub 30 coacts with the wall defining the entry port of the socket after rotation of the fastener relative thereto to retain the fastener in mounted posiion.

A study of Fig. 3 and the socket 28 disclosed therein leads to a more complete understanding of the usefulness of the present invention as well as to the operation of the safety key device. The socket 28 is composed of a body portion 32 with an entry port 34 opening into an annular recess or groove 36 which houses the prongs of a fluorescent tube. A contact arm 3% is located on each side of the port opening at and positioned within the confines of the annular recess 35. In the the annular recess 35. Thereafter the tube and prongs are rotated 90 during which 'rotation the contact arms 38 are sprung outwardly to position the prongs 44 therebetween. After said 90 rotation the tube is retained in this positioh due to the bowing of said contact arms 38 'as clearly shown in Figs. 3 and 4. After attachment of the fluorescent tube to a pair of seekers 28 as hreinabove described, the entry port 34, which leads into the annular recess 36, is exposed and readily accessible for accommodating thesaiety key 20.

as will be seen in Fig. 3, the safety key is ready to be many inserted through the entry 'p' s1-t;, ar;a in Fig. 4 has been inserted and rotated 90 to position the holding lug 26 transverse-to thfe entry port 38-. It will be noted in Fig. 4 that the nub or protuberance 30 -e xtends into the entry port or recess, and in this position retains the fastener against inadvertent or unauthorized rotation. The distance between the nub or protuberance 'ahd the nearest surface of the lug 26 may be slightly less than the thickness of the socket reenter 28 in the vicinity of the entry port. After insertion of the fastener into the entry po 'rt bf the seeker member, and during subsequent rof tatio-n to its mounted position, the head will be temporarily deflected as an incident to the en gagem'ehttf the hubs or prhtuberances with the outer periphery of the socket member. These nubs =30 ultimately spring into interlocking asso- 'ciati'oh with the elongatedehtry part 34'.

It should be noted that the hubs 8'!) are prefer ably iouhde'd so as to bresentcam's'urface's which perm-1t an operator to remove the safety key with facility for replacement or repair of fluorescent tu'bes'inthe nature. 7

shown in the various -figures a tab s t-mg head 48 eit'ends axially from the shank 2'2 "and the plane thereof eikteh'ds normal to fungi tudihal axis of the flhorescent tube a when the fastener is in Ihouht'ed position on the socket member. In thi's'pos'itio'n the wing head as serves as an indicator to show from a distance that the tube is locked in position. Its pr mary ii'ss'a r'e twb fo-ld, first to facilitate turning of the key, and-secondly, and of 7 equal or greater importance, to serve as an indicator t6 disclose wan operator whether or not thelug 26 of the fastener'is properly positioned to prevent remova1 of the tube from the socket. This indicator or kfiohhiay be highly-cblored so as to tender it easily discernible by an -operatorfor inspection purposes. It should 6f 'Sufli'cient size and shape t'd enhance the Visibility thereof.

In Fig. a modified form of the instant invention .is disclosed, wherein the head of the fastener has its opposed margins deflected toward the lug holding means so that said margins are spaced from the lug holding means 'a distance less than the thickness of the material of socket member with which it is to be used. In the embodiment disclosed in Fig. 5 the fastener head 24a is formed ar'cuately so as to position the opposite margins a thereof toward the clamping side of the lug 26a; It will be noted also that the corners of these margins are rounded so as to facilitate application; The are of the head 4 24a is formed on a shorter radius than the are presented by the complementary surface of the socket 28. Thus, when the fastener or key 20a is applied to the socket in the manner previously described in 'cpnhection the fastener 20, the opposite margins 30a of thehead are sprung sufficiently to permit complete insertion of the lu 2M. After the key has been turned so as to position the wing head or knob 48a transversely of the elongated (opening for accommodating the head 26a, as shown in Fig. 6, the resilient margins 30a of the head 24a resiliently bear against the complementary periphery of the socket 28. This frictional ehg'agement is suflicient to prevent unauthorized removal or loosening of the key 20a. Byem-ployingthe resilient head structure 24a, the necessity for using the locking lugs 30 of the fastener 20 is eliminated.

It should also be pointed out that the head 24 previously described, when occupying its locked pcsition as shown inFigs. 1, 4 and 7, serves as an abutment for the fluorescent tube 50. In installations where the socket members are spaced a distance which will permit or some axial shifting of the fluorescent tube, the extremity of th'e'h'eads 24 projecting beyond the inner surface of the depending portion of the socket 28,- as-c'learly shown iii Fig. "7, serves to limit the extent to Which this akial shifting of the fluorescent tube can take place Hence, the danger of loosely fitted mores cent tribes is reduced to a minimum.

While for purposes of illustration a particular commercial form of so'cket has been shown, it will be apparent that the invention is applicable for use with other forms of socket members. For eka'mpl, some commercial forms of socket members are equipped withtwo entry ports to permit mounting of the tube, and in such cases the safety key or fastener is usable. It will be understood that the invention is capable of other modificati'ons and changes from those disclosed in the drawing without departing from the scope of the appended claims.

The invention is hereby described as follows;

1. A one-piece q'uic'kly operable safety key for use with fluorescent light socket fixtures and made bf a dielectric material, Said key including a s'hankfa. resilient head at one end thereof, {finger gripping means associated with said head to fa ilitat' rotation of said shank, an elongated holding lug spaced axially from said headahd extending radially outwardly in opposite direction's from said shank, and means on the under surface "of said head extending in-a direction toward said holding lug adapted to engage a comelementary lightfsock'et fixture so as to resist rotation of said key when mounted in looking position on said socket, said resilient head and saidelbngated holding lug coacting to clampingly engage opposed surfaces of a complementary socket 'fl'iitu-re. I V

"2'. one piece quickly operable safety keyas set forth in claim 1, wherein the finger gripping means as'soriiated withthe head comprises a substantially fiat plate-like section containing the axis of said shank and adapted to be gripped by e a.

u 3-. Acne-piece quickly operable safety key as set "forth in claim 1-, wherein the means on the under surface of said resilient head consist of deforming opposite free extremities of said head portion in the direction of said holding lug adapted to engage a complementary surface of alight socket nature to resist rotation of said key when mounted in looking position 'on said socket.

4. A one-piece quickly operable safety key as set forth in claim 1, wherein locking lugs are provided on the under surface of the resilient head of said key which extend in a direction toward said holding lugs and are adapted to engage a complementary light socket fixture so as to resist rotation of said key when mounted in locking position on said socket.

LESTER J. SKLENAR.

References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date- Kennedy May 1, 1877 Dunn Dec. 28, 1886 Didierjean Jan. 13, 1914 Despard July 20, 1943 Bixby Dec. 14, 1943 FOREIGN PATENTS Country Date France Mar. 7, 1927 

